1. Field of the Invention
The present invention relates to a Field-Effect Transistor (FET) and, more particularly, to a Dielectric-Modulated Field-Effect Transistor (DMFET) and a method of fabricating the same.
2. Description of the Related Art
As the size of semiconductor devices shrinks, several physical limitations are encountered. A reduction in the device size has reached its limit due to the technical problems of lithography used in the semiconductor process (the wavelength of a light source, scattering of light, NA limit of the lens, the absence of a photoresist, and so on). Further, in the conventional semiconductor devices, an insulating layer was generally made of silicon-oxide (SiO2) . However, as the size of a device shrinks, physical limitations, such as breakdown and tunneling, have appeared. To overcome such physical limitations, active research has been done into devices having a novel structure. Of the devices, a molecule device has been proposed. The molecule device is a new concept of a device employing molecules as channels.
The molecule device can be used as a biosensor. The biosensor functions to detect specific molecules, such as enzyme or antibody, which constitute an organism. A method of detecting specific molecules comprises chemical, optical, and electrical methods. Of the methods, the electrical detection method can be used when the quantity of detection target samples is small, and is advantageous in that it has rapid detection. In the electrical detection method, a nano-gap is formed in an existing electrical device, a solution comprising a biomaterial is injected into the nano-gap, and specific materials are detected based on a variation in the electrical property of the device. Thus, the biomaterial formed in the nano-gap serves as an electrical sensor. As the size of a nano-gap reduces, sensitivity is increased and therefore a biomaterial can be detected more effectively.
To fabricate a structure having a nano-size width using the conventional silicon process is inefficient because of several steps of lithography processes, the alignment of a critical value, expensive equipment, environmental limitations of pressure or temperature, a long-time process, and so on. In order to overcome the limitations, a method of employing a breaking phenomenon of a metal nanowire, a method of forming a large-sized gap and reducing the gap size through an electrochemical deposition method, a method of employing ion beam etching, scanning probe lithography, etc., and so on have been introduced. However, the methods or an overall process thereof are problematic in that they are complicated, and have a limit to the formation of a nano-gap with high reproducibility, a low integration level, and a low sensitivity of a sensor.